An apparatus for imaging an object has a metering image sensor that comprises a plurality of pixels. The plurality of pixels is matrix-arrayed along vertical and horizontal directions. The apparatus also has an image sensor driver that drives the metering image sensor, which reads image-pixel signals of neighboring pixels among the plurality of pixels while mixing the image-pixel signals. The apparatus also has a pixel addition setting processor that sets a number of pixel addition of the metering image sensor with respect to at least one of at least one row and at least one column. The pixel addition setting processor sets different numbers of pixel addition to different pixel areas. The apparatus also has an exposure controller that controls an exposure of the metering image sensor and the photography image sensor.